That's all aliexpress. Alibaba is more industrial, negotiate for pricing; Aliexpress is a pure marketplace. With the subsidized shipping, I can often get something for <$2 that would be $8 on Amazon and $25 at Staples/BestBuy.
I needed a 1/8" stereo mini to 2 RCA male cable.
Staples: $15.59 - https://www.staples.com/Staples-7-3-5mm-to-Dual-RCA-Y-Adapte...
BestBuy: $9.99 - https://www.bestbuy.com/site/insignia-6-3-5mm-mini-to-rca-st...
Amazon: $4.76 - https://www.amazon.com/dp/B00IE7Z628
Aliexpress: $0.56 / $0.82 - https://www.aliexpress.com/item/1-Mini-Plug-3-5mm-Plug-Jack-...
US name brand stuff like this is particular troublesome for me because I am not living in the US. So I pay big shipping costs and then risk corrupt and extortionate customs actions. If I buy local the cost is just as high.
Also, have you seen anything that looks like Vex Robotics knockoffs? Same story - I have a Vex IQ kit and want to buy more but shipping costs are way more than the price of the item I want to buy.
If you want to buy LEGO knockoffs that's fine, but there are plenty of brands that are almost as cheap as Lepin and produce original (non-stolen) designs.
Lepin does as well, just under the XingBao name.
But the joke's on the both of them—I just buy them for the pieces, not for the set designs.
Honestly if Lego just sold big boxes of bulk technic pieces (like they do for their normal blocks), I'd probably just buy those instead.